Method, system and application of gas carrier belt cooperative treatment of tritium wastewater

Abstract

This invention relates to a method, system, and application for the gas-carrier synergistic treatment of tritium wastewater. The method is a three-stage synergistic extraction and removal of tritium involving gas, liquid, and solid phases, comprising at least one single-stage treatment process. In this single-stage process, an appropriate amount of carrier gas is introduced into a solid-liquid adsorption system, and a gas-liquid-solid three-phase contact structure is constructed. The adsorption and isotope exchange of tritium-bearing water by the solid adsorbent material enriches tritium in the solid adsorbent material. Simultaneously, the carrier gas, through gas-liquid interface renewal and gas-liquid mass transfer, carries away water from the liquid phase as water vapor, forming a carrier gas flow carrying tritium-bearing water vapor, ultimately achieving tritium wastewater separation. The system of this invention has a simple structure and mild operating conditions; it significantly improves the single-stage tritium removal rate and adsorption capacity per unit mass under normal pressure and low temperature conditions, while also possessing the characteristics of simple structure, low energy consumption, and ease of engineering scale-up.

Description

Technical Field

[0001] This invention relates to the field of nuclear wastewater treatment technology, specifically to a method, system, and application for the co-treatment of tritium wastewater using a gas carrier. Background Technology

[0002] Nuclear power plants, research reactors, and isotope production facilities generate large amounts of tritium-containing liquid effluents during normal operation and decommissioning. Tritium typically exists as tritized water (HTO or T2O), whose physicochemical properties are extremely similar to ordinary water, with minimal differences in boiling point, vapor pressure, and reactivity. This makes traditional separation methods based on phase equilibrium differences difficult to achieve efficient and economical tritium removal under low to medium concentration conditions. Current mainstream technologies for tritium separation include cryogenic distillation and isotope distillation, electrolysis-distillation combinations, catalytic isotope exchange-distillation combinations, and gas diffusion and liquid membrane separation. These processes largely rely on large-volume towers and high-energy-consuming operations, resulting in problems such as high equipment investment, high operating costs, slow start-up and shutdown, and complex operation and maintenance when treating large flow rates of tritium-containing wastewater with an activity of 1–100 MBq / L. Meanwhile, to reduce energy consumption and equipment complexity, tritium removal methods based on adsorption / isotope exchange have attracted attention. For example, tritium enrichment and removal can be achieved using coal-based porous carbon, polymer adsorbents, or sulfonic acid resins. However, under static or simple stirring conditions, the mass transfer rate of the adsorption process is limited, the isotope exchange kinetics are slow, and a long contact time is required to reach equilibrium, making it difficult to further improve the single-stage tritium removal rate. Summary of the Invention

[0003] Addressing the current technological challenges facing the industry, the inventors discovered that introducing an appropriate amount of inert gas into a solid-liquid adsorption system and constructing a gas-liquid-solid three-phase contact structure can leverage the gas carrying effect. This allows for continuous renewal of the liquid film and enhanced mass transfer between the liquid and solid phases. Furthermore, water can be transferred to the gas phase as vapor, enabling tritium separation in a downstream cold trap, thus creating a synergistic effect with solid-phase adsorption. In addition, tritium is not only an environmental risk factor requiring controlled emissions but also a crucial resource for nuclear fusion. Therefore, developing a simple, low-energy-consumption tritium removal process that is easily integrated with subsequent resource utilization is of great significance.

[0004] Therefore, the gas-carrier synergistic adsorption technology for tritium removal of the present invention has a simple system structure, mild operating conditions, and can be upgraded based on existing adsorption units, thus overcoming the shortcomings of existing technologies in terms of kinetics and economy. The gas-carrier synergistic treatment method and system for tritium wastewater of the present invention significantly improves the single-stage tritium removal rate and adsorption capacity per unit mass under normal pressure and low temperature conditions, while also possessing the characteristics of simple structure, low energy consumption, and ease of engineering scale-up.

[0005] On one hand, the present invention provides a method for gas-carrier synergistic treatment of tritium wastewater, wherein the method is a three-stage synergistic extraction method for removing tritium using gas phase, liquid phase and solid phase, including at least one single-stage treatment process, each single-stage treatment process specifically including the following steps: Step 1): The tritium wastewater to be treated is introduced into a closed tritium removal reactor, solid adsorbent is added, and the reaction is carried out at a temperature of 25±2℃ for 12~72h to form a liquid-solid two-phase system. Step 2): The carrier gas source is introduced into the inner cavity of the tritium removal reactor through a gas distributor. The reaction occurs at a temperature of 5–100°C, forming a gas-liquid-solid three-phase contact structure. At the same time, a carrier gas flow carrying tritized water vapor is formed. The tritium activity concentration in the tritized water vapor is lower than the tritium activity concentration in the tritium wastewater. Step 3): The carrier gas flow is introduced into the cold trap unit and condensed and separated at -20 to 10°C to obtain treated water and carrier gas. The carrier gas is circulated back to the carrier gas source and the treated water is collected.

[0006] Controlling the reaction temperature in step 2) within a suitable range is more conducive to improving the overall tritium removal effect of the system. If the temperature is too high, it will be detrimental to gas-liquid mass transfer, adsorption equilibrium, and effective condensation and recovery of tritized water vapor by the cold trap in the system, thus leading to a decrease in the overall tritium removal effect.

[0007] Similarly, in step 3), the condensation separation temperature of the cold trap unit needs to be appropriate. If the condensation separation temperature of the cold trap unit is too high, the tritium water collection efficiency will decrease.

[0008] Furthermore, the gas-carrier co-treatment method for tritium wastewater according to the present invention includes a single-stage treatment process. Step 3) further includes: detecting the tritium activity concentration and tritium removal rate of the treated water; if the tritium activity concentration of the treated water is less than or equal to 100 Bq / L, it is stored or discharged; if the tritium activity concentration of the treated water is greater than 100 Bq / L, steps 1) to 3 are repeated as a new batch of tritium wastewater to be treated.

[0009] Furthermore, in the gas-carrier co-treatment method for tritium wastewater described in this invention, the method includes at least two single-stage treatment processes, which are connected in series or in parallel. When the single-stage treatment processes of the method are connected in series, step 3) of the last single-stage treatment process further includes: detecting the tritium activity concentration and tritium removal rate of the condensed and separated treated water; if the tritium activity concentration of the treated water in the last single-stage treatment process is greater than 100 Bq / L, it is recycled back to any single-stage treatment process as a new batch of tritium wastewater to be treated, and steps 1) to 3) are repeated; if the tritium activity concentration of the treated water in the last single-stage treatment process is less than or equal to 100 Bq / L, it is stored or discharged. When the single-stage treatment processes of the method are set in parallel, step 3) of each single-stage treatment process further includes: detecting the tritium activity concentration and tritium removal rate of the condensed and separated treated water; if the tritium activity concentration of the treated water in each single-stage treatment process is greater than 100 Bq / L, it is recycled back to each single-stage treatment process as a new batch of tritium wastewater to be treated, and steps 1) to 3) are repeated; if the tritium activity concentration of the treated water in each single-stage treatment process is less than or equal to 100 Bq / L, it is stored or discharged. When multiple single-stage treatment processes of the method are connected in series to form multiple sets of series single-stage treatment processes, and each set of series single-stage treatment processes is then connected in parallel; step 3) of the last single-stage treatment process of each set of series single-stage treatment processes further includes: the tritium activity concentration of the condensed and separated treated water needs to be detected. If the tritium activity concentration of the treated water of the last single-stage treatment process is greater than 100 Bq / L, then it is recycled back to any single-stage treatment process as a new batch of tritium wastewater to be treated, and steps 1) to 3) are repeated; if the tritium activity concentration of the treated water of the last single-stage treatment process is less than or equal to 100 Bq / L, then it is stored or discharged.

[0010] Furthermore, in the gas-carrier co-processing method for tritium wastewater described in this invention, the method treats n batches of tritium wastewater, where n≥2; the method further includes step 4): determining whether the solid adsorbent material in the tritium removal reactor needs to be replaced based on the tritium removal rate detected in step 3); when the tritium removal rate of the nth batch of treated water decreases by K compared to the tritium removal rate of the first batch of treated water, and K≥40%, the tritium-enriched solid adsorbent material is discharged from the tritium removal reactor, and new solid adsorbent material is added; the tritium-enriched solid adsorbent material is treated as tritium-containing solid waste.

[0011] Furthermore, in the gas-carrying co-treatment method for tritium wastewater described in this invention, in step 2), the carrier gas is one or a combination of two inert gases or weakly reactive gases, and the flow rate of the carrier gas is 0.001–10 L / min. If the flow rate of the carrier gas is too low, the carrying effect of the gas on the tritized water vapor is weak, the gas-liquid interface renewal rate is slow, resulting in limited migration and condensation recovery of the tritized water vapor; conversely, when the flow rate of the carrier gas is too high, the gas residence time is shortened, the stability of the gas-liquid-solid three-phase contact decreases, and the condensation recovery process may be affected. Therefore, controlling the flow rate of the carrier gas within a suitable range is more conducive to achieving a balance between tritium removal rate, treatment time, and tritium water collection efficiency.

[0012] Furthermore, in the gas-carrier co-treatment method for tritium wastewater described in this invention, in step 1), the mass ratio of the solid adsorbent material to the tritium wastewater is (1:1) to (1:10), and in step 2), the volume ratio of the carrier gas introduced to the tritium wastewater is (1:100) to (1:1).

[0013] The mass ratio of solid adsorbent to tritium wastewater, and the volume ratio of the carrier gas to tritium wastewater, must both be within the aforementioned ranges. Only then can the solid adsorbent, liquid wastewater, and carrier gas in the system achieve sufficient gas-liquid-solid three-phase contact, which is beneficial for the synergistic effects of enhanced mass transfer, isotope exchange, and tritized water vapor migration. It also facilitates a balance between tritium removal rate, adsorption capacity, and tritium water collection efficiency. If the proportion of solid adsorbent is too high, most of the tritium-containing water will be absorbed or retained by the adsorbent, making it difficult to effectively collect condensate and hindering continuous tritium water transport and condensation separation.

[0014] The present invention provides a gas-carrier synergistic treatment method for tritium wastewater. This method constructs a three-phase contact system of tritium-containing water, solid adsorbent material, and carrier gas. An appropriate amount of carrier gas is introduced into the tritium removal reactor, dispersing it in the liquid phase as fine bubbles to enhance mass transfer and isotope exchange between the liquid phase and the solid adsorbent material. The low-activity tritized water vapor carried by the carrier gas during its ascent is introduced into a downstream cold trap or subjected to multiple adsorption processes for further tritium removal, achieving multi-stage synergistic tritium removal across the gas, liquid, and solid phases. By adjusting the carrier gas flow rate, adsorbent material loading, cold trap temperature, and operating time, an optimized balance between tritium removal efficiency and energy consumption is achieved.

[0015] In this invention, in the gas-liquid-solid three-phase contact structure, the solid adsorbent material adsorbs and exchanges isotopes with tritized water, enriching tritium in the solid adsorbent material. At the same time, the carrier gas carries away water in the liquid phase as water vapor through gas-liquid interface renewal and gas-liquid mass transfer, forming a carrier gas flow carrying tritized water vapor. The tritium activity concentration in the tritized water vapor is lower than the tritium activity concentration in the tritium wastewater.

[0016] On the other hand, the present invention provides a system for gas-carrier co-treatment of tritium wastewater, the system being used to implement the gas-carrier co-treatment method for tritium wastewater as described in any of the above claims; The system includes one or more tritium removal units and a carrier gas source, the carrier gas source being used to store the carrier gas; the carrier gas is one or a combination of two of inert gases or weakly reactive gases, and each of the tritium removal units performs a single-stage processing procedure; The tritium removal unit includes a tritium removal reactor, a flow control unit, a cold trap unit, a gas loop pipeline, and tritium water inlet and outlet pipelines. The flow control unit is a control valve. The tritium removal reactor is an openable sealed unit, including an inner cavity for containing tritium wastewater and solid adsorbent material, 1 to 5 gas distributors disposed on the inner wall of the tritium removal reactor, and a tritium removal reactor inlet and a tritium removal reactor gas outlet disposed on the inner wall of the tritium removal reactor; both the tritium removal reactor inlet and the tritium removal reactor gas outlet are equipped with flow control units. The gas distributor is connected to the carrier gas source via a pipeline, and the gas inlet of the gas distributor is equipped with a flow control unit; The gas outlet of the tritium removal reactor is connected to the cold trap unit. The gas inlet of the cold trap unit is equipped with a gas flow control unit. The gas outlet of the cold trap unit is connected to the carrier gas source through a gas loop pipeline. The tritium water inlet pipeline is connected to the water inlet of the tritium removal reactor. When the system has multiple tritium removal units, the tritium removal units are connected in parallel or in series. When the detritium removal units are connected in series, the outlet of the cold trap unit of the previous detritium removal unit is connected to the inlet of the detritium removal reactor of the next detritium removal unit.

[0017] The gas carrier co-processing system for tritium wastewater of the present invention includes a tritium removal reactor, a gas distributor, a carrier gas source and circulation system, a cold trap unit, inlet and outlet pipelines, etc., enabling the above method to operate stably under intermittent or continuous conditions.

[0018] Furthermore, in the gas-carrier co-treatment system for tritium wastewater described in this invention, the inert gas is argon or helium, and the weakly reactive gas is nitrogen or air.

[0019] Furthermore, in the gas-carrier co-treatment system for tritium wastewater described in this invention, the solid adsorbent material is a material with hydrogen-containing functional groups and / or ion exchange groups capable of participating in hydrogen / tritium isotope exchange, and the solid adsorbent material is a hydrophilic polymer adsorbent material.

[0020] Furthermore, in the gas-carrier co-treatment system for tritium wastewater described in this invention, the solid adsorbent is a sulfonic acid-type strong acid cation exchange resin, or a modified sulfonic acid-type strong acid cation exchange resin, or polyvinyl alcohol.

[0021] The resin backbone of the sulfonic acid type strong acid cation exchange resin is cross-linked polystyrene or acrylic acid copolymer, and the surface of the modified sulfonic acid type strong acid cation exchange resin contains -SO3H functional groups.

[0022] Furthermore, in the gas-carrier co-treatment system for tritium wastewater described in this invention, the modified sulfonic acid type strong acid cation exchange resin is a composite system of hydrophilic polymer adsorbent and acidic sulfonic acid type strong acid cation exchange resin. Furthermore, the hydrophilic polymer adsorbent is selected from one or more of polyvinyl alcohol, polyacrylic acid and its salts, carboxymethyl cellulose, chitosan or its derivatives.

[0023] In another aspect, the present invention provides an application of a gas-carrier co-processing system for tritium wastewater, wherein the system is any of the gas-carrier co-processing systems for tritium wastewater described above, and the system is applied to the reduction of low-to-medium concentration tritium wastewater and the recovery of tritium resources generated by nuclear power plants, research reactors, isotope production devices or nuclear facilities; wherein the tritium activity concentration of the low-to-medium concentration tritium wastewater is 1 MBq / L to 100 MBq / L.

[0024] The beneficial effects of this invention are: The method and system for gas-carrier synergistic treatment of tritium wastewater of the present invention significantly improve the single-stage tritium removal rate and adsorption capacity in the process of tritium wastewater reduction and tritium resource recovery. Under the same resin dosage and treatment time, the tritium removal rate of the single-stage treatment process can be increased by more than 18% after introducing a gas carrier, and the adsorption capacity per unit mass is also greatly improved. The synergistic effect of the carrier gas and adsorption can effectively improve the tritium separation rate.

[0025] The gas-carrier co-processing method and system of the present invention enhances mass transfer and shortens equilibrium time during the tritium wastewater reduction and tritium resource recovery process. The continuous generation and collapse of fine bubbles significantly reduces the liquid film thickness, increases the renewal frequency of the liquid-solid interface, and improves the hydrogen / tritium isotope exchange rate, thereby achieving a higher tritium removal rate in a shorter time.

[0026] The system structure for gas-carrier co-treatment of tritium wastewater of the present invention is simple and easy to modify and scale up. It only requires the addition of a carrier gas circuit and a cold trap unit to the conventional adsorption or resin exchange unit, without the need for a high-temperature and high-pressure system or a large distillation column, and can be used in series or parallel in an modular manner in existing nuclear wastewater treatment systems.

[0027] The gas-carrier co-treatment method for tritium wastewater of this invention features low energy consumption and high safety. The process operates under normal pressure and low temperature conditions, using an inert or weakly reactive carrier gas. The system can be designed as a closed-loop system, reducing the risk of gaseous tritium emissions. Overall energy consumption is significantly lower than separation processes such as distillation and rectification. Furthermore, it facilitates integration with tritium resource utilization; the tritium-rich phase obtained in the cold trap unit can serve as a raw material for subsequent high-value applications such as tritium-volt batteries and tritium functionalized materials, thus contributing to the construction of an integrated "emission reduction-tritium removal-utilization" technology route. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a gas carrier-assisted adsorption and tritium removal device according to a specific embodiment two of the present invention; Figure 2 Bar charts comparing tritium removal rate and adsorption capacity in Examples 1, 3, and 4 of the present invention; Figure 3 This is a bar chart comparing the tritium removal rate and adsorption amount of Example 1 and Comparative Example 1 of the present invention. Figure 4An optical photograph of the sulfonic acid type strong acid cation exchange resin in Example 1 of the present invention; Figure 5 This is a schematic diagram of the gas-liquid-solid three-phase contact structure in the tritium removal reactor of Embodiment 2 of the present invention. Detailed Implementation

[0029] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments are now described in detail with reference to the accompanying drawings. The described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the detailed embodiments, conventional conditions or conditions provided by the manufacturer shall apply.

[0030] In the following description, when referring to the accompanying drawings, the same numbers in different drawings denote the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. Specific implementation method one: The present invention discloses a gas-carrier synergistic treatment method for tritium wastewater. The method comprises a three-stage synergistic extraction method involving gas, liquid, and solid phases for tritium removal, including at least one single-stage treatment process. Each single-stage treatment process specifically includes the following steps: Step 1): The tritium wastewater to be treated is introduced into a closed tritium removal reactor, solid adsorbent is added, and the reaction is carried out at a temperature of 25±2 ℃ for 12-72 h to form a liquid-solid two-phase system. Step 2): The carrier gas source is introduced into the inner cavity of the above-mentioned tritium removal reactor through a gas distributor. The reaction is carried out at a temperature of 5-100°C to form a gas-liquid-solid three-phase contact structure, and a carrier gas flow carrying tritized water vapor is formed at the same time. The tritium activity concentration in the above-mentioned tritized water vapor is lower than the tritium activity concentration in the tritium wastewater. Step 3): The above-mentioned carrier gas flow is introduced into the cold trap unit and condensed and separated at -20 to 10°C to obtain treated water and carrier gas. The carrier gas is circulated back to the carrier gas source and the treated water is collected.

[0032] In some embodiments, the above method includes a single-stage treatment process, and step 3) further includes: detecting the tritium activity concentration and tritium removal rate of the treated water; if the tritium activity concentration of the treated water is less than or equal to 100 Bq / L, then storing or discharging; if the tritium activity concentration of the treated water is greater than 100 Bq / L, then repeating steps 1) to 3) as a new batch of tritium wastewater to be treated.

[0033] In some implementations, the above method includes two single-stage processing procedures, which are connected in series or in parallel.

[0034] In some implementations, the above method includes two or more single-stage processing procedures, which are connected in series or in parallel.

[0035] In some embodiments, the single-stage treatment processes of the above method are arranged in series. Step 3) of the last single-stage treatment process further includes: detecting the tritium activity concentration and tritium removal rate of the condensed and separated treated water; if the tritium activity concentration of the treated water of the last single-stage treatment process is greater than 100 Bq / L, it is recycled back to any single-stage treatment process as a new batch of tritium wastewater to be treated, and steps 1) to 3) are repeated; if the tritium activity concentration of the treated water of the last single-stage treatment process is less than or equal to 100 Bq / L, it is stored or discharged. In some embodiments, the single-stage treatment processes of the above method are arranged in parallel. Step 3) of each single-stage treatment process further includes: detecting the tritium activity concentration and tritium removal rate of the condensed and separated treated water; if the tritium activity concentration of the treated water in each single-stage treatment process is greater than 100 Bq / L, it is recycled back to each single-stage treatment process as a new batch of tritium wastewater to be treated, and steps 1) to 3) are repeated; if the tritium activity concentration of the treated water in each single-stage treatment process is less than or equal to 100 Bq / L, it is stored or discharged. In some embodiments, the multiple single-stage treatment processes of the above method are connected in series to form multiple sets of series single-stage treatment processes, and each set of series single-stage treatment processes is then connected in parallel; step 3) of the last single-stage treatment process of each set of series single-stage treatment processes further includes: the tritium activity concentration of the condensed and separated treated water needs to be detected; if the tritium activity concentration of the treated water of the last single-stage treatment process is greater than 100 Bq / L, then it is recycled back to any single-stage treatment process as a new batch of tritium wastewater to be treated, and steps 1) to 3) are repeated; if the tritium activity concentration of the treated water of the last single-stage treatment process is less than or equal to 100 Bq / L, then it is stored or discharged.

[0036] In some embodiments, the above method treats n batches of tritium wastewater, where n≥2; the above method further includes step 4): determining whether the solid adsorbent material in the tritium removal reactor needs to be replaced based on the tritium removal rate detected in step 3); when the tritium removal rate of the nth batch of treated water decreases by K compared to the tritium removal rate of the first batch of treated water, and K≥40%, the tritium-enriched solid adsorbent material is discharged from the tritium removal reactor, and new solid adsorbent material is added; the tritium-enriched solid adsorbent material is treated as tritium-containing solid waste.

[0037] In some embodiments, in step 2) above, the carrier gas is one or a combination of two of inert gases or weakly reactive gases, and the flow rate of the carrier gas is 0.001 to 10 L / min.

[0038] In some embodiments, in step 1), the mass ratio of the solid adsorbent material to the tritium wastewater is (1:1) to (1:10).

[0039] In some embodiments, the volume ratio of the carrier gas introduced in step 2) above to the tritium wastewater is (1:100) to (1:1).

[0040] The present invention provides a gas-carrier synergistic treatment method for tritium wastewater. This method constructs a three-phase contact system of tritium-containing water, solid adsorbent material, and carrier gas. An appropriate amount of carrier gas is introduced into the tritium removal reactor, dispersing it in the liquid phase as fine bubbles to enhance mass transfer and isotope exchange between the liquid phase and the solid adsorbent material. The low-activity tritized water vapor carried by the carrier gas during its ascent is introduced into a downstream cold trap or subjected to multiple adsorption processes for further tritium removal, achieving multi-stage synergistic tritium removal across the gas, liquid, and solid phases. By adjusting the carrier gas flow rate, adsorbent material loading, cold trap temperature, and operating time, an optimized balance between tritium removal efficiency and energy consumption is achieved. Specific Implementation Method Two: The present invention provides a system for gas-carrier co-treatment of tritium wastewater, wherein the system is used to implement the gas-carrier co-treatment method for tritium wastewater described in any of the above claims; The system includes one or more tritium removal units and a carrier gas source, the carrier gas source being used to store the carrier gas; the carrier gas is one or a combination of two of inert gases or weakly reactive gases, and each of the above tritium removal units performs a single-stage processing procedure; The aforementioned tritium removal unit includes a tritium removal reactor, a flow control unit, a cold trap unit, a gas circuit pipeline, and a tritium water inlet pipeline. The aforementioned flow control unit is a control valve. The aforementioned tritium removal reactor is an openable sealed unit, including an inner cavity for containing tritium wastewater and solid adsorbent material, 1 to 5 gas distributors disposed on the inner wall of the aforementioned tritium removal reactor, and a tritium removal reactor inlet and a tritium removal reactor gas outlet disposed on the inner wall of the aforementioned tritium removal reactor; both the aforementioned tritium removal reactor inlet and the tritium removal reactor gas outlet are equipped with flow control units; The gas distributor is connected to the carrier gas source via a pipeline, and the gas inlet of the gas distributor is equipped with a flow control unit. The gas outlet of the above-mentioned tritium removal reactor is connected to the cold trap unit. The gas inlet of the cold trap unit is equipped with a gas flow control unit. The gas outlet of the cold trap unit is connected to the carrier gas source through a gas loop pipeline. The tritium water inlet pipeline is connected to the water inlet of the tritium removal reactor. When the system has multiple tritium removal units, the tritium removal units are connected in parallel or in series. When the detritium removal units are connected in series, the outlet of the cold trap unit of the previous detritium removal unit is connected to the inlet of the detritium removal reactor of the next detritium removal unit.

[0042] In some implementations, such as Figure 1 As shown, the system for co-processing tritium wastewater with gas carrier has three tritium removal units, which are connected in parallel. Figure 1 In this context, substandard water refers to treated water with a tritium activity concentration greater than 100 Bq / L. Substandard water is returned to the reactor inlet, which is the tritium removal reactor. Standard-compliant water refers to treated water with a tritium activity concentration less than or equal to 100 Bq / L.

[0043] In some embodiments, the system for co-processing tritium wastewater with gas carrier has three tritium removal units connected in series.

[0044] The gas-carrier co-processing system for tritium wastewater of the present invention can operate stably under intermittent or continuous conditions.

[0045] In some embodiments, the inert gas is argon or helium, and the weakly reactive gas is nitrogen or air.

[0046] In some embodiments, the aforementioned solid adsorbent material is a material having hydrogen-containing functional groups and / or ion exchange groups capable of participating in hydrogen / tritium isotope exchange.

[0047] In some embodiments, the aforementioned solid adsorbent is a hydrophilic polymer adsorbent.

[0048] In some embodiments, the solid adsorbent is a sulfonic acid-type strong acid cation exchange resin.

[0049] In some embodiments, the solid adsorbent is a modified sulfonic acid type strong acid cation exchange resin.

[0050] In some embodiments, the solid adsorbent material is polyvinyl alcohol.

[0051] In some embodiments, the resin backbone of the above-mentioned sulfonic acid type strong acid cation exchange resin is cross-linked polystyrene or acrylic acid copolymer.

[0052] In some embodiments, the surface of the modified sulfonic acid type strong acid cation exchange resin contains -SO3H functional groups.

[0053] In some embodiments, the modified sulfonic acid type strong acid cation exchange resin is a composite system of hydrophilic polymer adsorbent and acidic sulfonic acid type strong acid cation exchange resin.

[0054] In some embodiments, the hydrophilic polymer adsorbent is selected from one or more of polyvinyl alcohol, polyacrylic acid and its salts, carboxymethyl cellulose, chitosan or its derivatives. Specific implementation method three: This invention discloses an application of a gas-carrier co-processing system for tritium wastewater. The system is any one of the aforementioned gas-carrier co-processing systems for tritium wastewater. This system is applied to the reduction of low-to-medium concentration tritium wastewater and the recovery of tritium resources generated by nuclear power plants, research reactors, isotope production facilities, or nuclear facilities. The tritium activity concentration of the aforementioned low-to-medium concentration tritium wastewater is 1 MBq / L to 100 MBq / L.

[0056] The present invention will be further described in detail below with reference to specific embodiments. Example 1:

[0057] This invention relates to a method, system, and application for the co-processing of tritium wastewater using a gas carrier, as well as the recovery of tritium wastewater from liquid effluents of nuclear facilities.

[0058] The system for co-processing tritium wastewater with gas carrier gas in this embodiment 1 includes a tritium removal unit and a carrier gas source. The carrier gas source is used to store the carrier gas. The carrier gas is high-purity argon. Each tritium removal unit performs a single-stage treatment process.

[0059] The tritium removal unit includes a tritium removal reactor, a flow control unit, a cold trap unit, a gas loop pipeline, and a tritium water inlet pipeline. The flow control unit is a control valve.

[0060] The tritium removal reactor is a closed unit that can be opened, including an inner cavity for containing tritium wastewater and solid adsorbent material, a gas distributor installed on the inner wall of the tritium removal reactor, a tritium removal reactor inlet and a tritium removal reactor gas outlet installed on the inner wall of the tritium removal reactor; both the tritium removal reactor inlet and the tritium removal reactor gas outlet are equipped with flow control units.

[0061] The gas distributor is connected to the carrier gas source via a pipeline, and the gas inlet of the gas distributor is equipped with a flow control unit.

[0062] The gas outlet of the tritium removal reactor is connected to the cold trap unit. The gas inlet of the cold trap unit is equipped with a gas flow control unit. The gas outlet of the cold trap unit is connected to the carrier gas source through a gas loop pipeline. The tritium water inlet pipeline is connected to the water inlet of the tritium removal reactor. When the system has multiple tritium removal units, the tritium removal units are connected in parallel or in series. When the detritium removal units are connected in series, the outlet of the cold trap unit of the previous detritium removal unit is connected to the inlet of the detritium removal reactor of the next detritium removal unit.

[0063] The solid adsorbent is a commercial sulfonic acid-type strong acid cation exchange resin, such as... Figure 4 As shown. In this Example 1, the commercial sulfonic acid type strong acid cation exchange resin was purchased from Guangdong Fangxin Biotechnology Co., Ltd. as perfluorosulfonic acid resin (-H), with an analytical purity of 98%.

[0064] In this example 1, the tritium wastewater is a liquid effluent from a nuclear facility, with an initial tritium activity concentration of 701.6 kBq / L.

[0065] The gas-carrier synergistic treatment method for tritium wastewater in Example 1 is a three-stage synergistic extraction method involving gas phase, liquid phase, and solid phase for tritium removal. It is a single-stage treatment process, and each single-stage treatment process specifically includes the following steps: Step 1): The tritium wastewater to be treated is introduced into a closed tritium removal reactor, and 30.0 g of sulfonic acid-type strong acid cation exchange resin (solid adsorbent) is added. The reaction is carried out at 25°C for 48 h to form a liquid-solid two-phase system. The tritium wastewater is a liquid effluent from a nuclear facility, with an initial tritium activity concentration of 701.6 kBq / L. The mass ratio of solid adsorbent to tritium wastewater is 2:3.

[0066] Step 2): The carrier gas source is introduced into the inner cavity of the tritium removal reactor through a gas distributor to form a gas-liquid-solid three-phase contact structure. The reaction is carried out at a temperature of 25°C, which enriches tritium in the solid adsorbent material. At the same time, the carrier gas carries away water in the liquid phase as water vapor through gas-liquid interface renewal and gas-liquid mass transfer, forming a carrier gas flow containing low-activity water vapor. The carrier gas flow rate is 0.05 L / min.

[0067] Step 3): The gas stream carrying low-activity water vapor is introduced into the cold trap unit and condensed and separated at -5°C to obtain treated water and carrier gas. The carrier gas is circulated back to the carrier gas source and the treated water is collected. Step 4): After all the flowable tritium wastewater in the tritium removal reactor is transferred to the cold trap unit along with the carrier gas, the tritium-enriched solid adsorbent material is discharged from the tritium removal reactor; the tritium-enriched solid adsorbent material is treated as tritium-containing solid waste.

[0068] After reacting in the tritium removal reactor for 8 hours, all the flowable tritium wastewater was transferred to the cold trap unit along with the carrier gas. After the gas supply was stopped, the tritium activity concentration of the treated water and the tritium removal rate were measured, and the overall tritium removal rate and the adsorption capacity per unit mass of the resin were calculated. Example 2:

[0069] The only difference between Example 2 and Example 1 is that the ratio of solid adsorbent material to tritium-containing wastewater is 1:1. Figure 5 The diagram shows the gas-liquid-solid three-phase contact structure in the tritium removal reactor. Example 3:

[0070] The only difference between Example 3 and Example 1 is that the ratio of solid adsorbent material to tritium-containing wastewater is 1:3. Example 4:

[0071] The only difference between Example 4 and Example 1 is that the ratio of solid adsorbent material to tritium-containing wastewater is 1:4.

[0072] like Figure 2 As shown, orange represents the detection results of Example 1, purple represents the detection results of Example 3, and gray represents the detection results of Example 4. The detection results of Examples 1-4 show that when the solid-liquid ratio is 1:4, the single-stage tritium removal rate is 9.4%, and the adsorption capacity per unit mass of adsorbent material is 263.5 Bq / g. When the solid-liquid ratio is 1:3, the single-stage tritium removal rate increases to 12.3%, and the adsorption capacity per unit mass is 259.4 Bq / g. The overall change is relatively small, indicating that the tritium removal effect of the system is still relatively limited at this solid adsorbent material addition ratio. When the solid-liquid ratio is increased to 2:3, the single-stage tritium removal rate significantly increases to 29.1%, and the adsorption capacity per unit mass increases to 306.2 Bq / g, indicating that the system exhibits a better overall treatment effect. Example 5:

[0073] The only difference between Example 5 and Example 1 is that the flow rate of the carrier gas argon is 0.01 L / min. Example 6:

[0074] The only difference between Example 6 and Example 1 is that the flow rate of the carrier gas argon is 0.10 L / min.

[0075] Analysis of the detection results in Examples 5 and 6 shows that when the carrier gas flow rate is 0.01 L / min, the single-stage tritium removal rate is 28%, and the experiment is completed in 24 hours; when the carrier gas flow rate is further increased to 0.10 L / min, the single-stage tritium removal rate is 29%, and the experiment is completed in 16 hours. Example 7:

[0076] The only difference between Example 7 and Example 1 is that in step 2), the carrier gas is dispersed in the liquid phase of the liquid-solid two-phase system in the form of fine bubbles to form a gas-liquid-solid three-phase contact structure, and the reaction is carried out at a temperature of 5°C. The single-stage tritium removal rate in Example 7 is 28%. Example 8:

[0077] The only difference between Example 8 and Example 1 is that in step 2), the carrier gas is dispersed in the liquid phase of the liquid-solid two-phase system in the form of fine bubbles to form a gas-liquid-solid three-phase contact structure, and the reaction is carried out at a temperature of 60°C. The single-stage tritium removal rate in Example 8 is 22%. Example 9:

[0078] The only difference between this embodiment 9 and embodiment 1 is that in step 3), the condensation separation temperature of the cold trap unit is 0°C.

[0079] Example 10: The only difference between this embodiment 10 and embodiment 1 is that in step 3), the condensation separation temperature of the cold trap unit is -10℃.

[0080] Example 11: The only difference between this embodiment 11 and embodiment 1 is that in step 3), the condensation separation temperature of the cold trap unit is -20°C.

[0081] Analysis of the test results in Examples 9-11 showed that the single-stage tritium removal rate of the system was 27% when the cold trap temperatures were 0℃, -10℃, and -20℃, respectively. However, further analysis of the tritium water collection in the cold trap revealed that the tritium water collection efficiency was higher when the condensation separation temperature of the cold trap unit was -10℃ and -20℃. The analysis suggests that the cold trap temperature has a relatively small impact on the single-stage tritium removal rate, but a significant impact on the condensation and recovery efficiency of tritized water vapor. Therefore, controlling the cold trap temperature within a lower range is more conducive to the effective collection of tritium water.

[0082] Example 12: The only difference between Example 12 and Example 1 is that the solid adsorbent is polyvinyl alcohol (PVA, analytical grade, Maclean, type 1799).

[0083] The test results show that when PVA is used as the solid adsorbent, the single-stage tritium removal efficiency can reach 26%, indicating that PVA has good applicability in the gas-liquid-solid three-phase synergistic tritium removal system of this invention. Analysis suggests that PVA's three-dimensional porous structure provides a large gas-liquid-solid interface, which is beneficial for the penetration, retention, and mass transfer of tritium-containing wastewater within the material. Simultaneously, the PVA molecular chain contains a large number of hydroxyl groups, which can form hydrogen bonds with tritized water and, to a certain extent, promote the hydrogen / tritium isotope exchange process. Therefore, PVA can achieve a high single-stage tritium removal efficiency through multiple mechanisms, including enhanced mass transfer via its porous structure, isotope exchange promoted by hydroxyl groups, and the transport of tritized water vapor facilitated by the carrier gas.

[0084] Example 13: The only difference between Example 13 and Example 1 is that the gas-carrier co-treatment method for tritium wastewater in Example 13 includes at least three single-stage treatment processes, which are connected in series. That is, the method described in Example 1 is followed three times sequentially: first, the original tritium-containing wastewater undergoes a first treatment; the resulting treated water is used as feed for the second treatment; and then the treated water from the second treatment is used as feed for the third treatment. The treatment conditions for each stage are the same as in Example 1.

[0085] Analysis of the detection results in Example 13 shows that after the first treatment, the tritium activity concentration in the treated water decreased by approximately 28%; after the second treatment, the cumulative tritium removal rate increased to approximately 45%; and after the third treatment, the cumulative tritium removal rate further increased to approximately 58%. The results indicate that the method of the present invention has a good cascade treatment effect, and the overall tritium removal rate can be further improved through multi-stage series connection, making it suitable for the treatment of tritium-containing wastewater requiring a higher degree of removal.

[0086] Comparative Example 1: The only difference between Comparative Example 1 and Example 1 is that no carrier gas was introduced.

[0087] like Figure 3 As shown, the test results of Comparative Example 1 indicate that, under conditions without the participation of a carrier gas, the single-stage tritium removal rate is approximately 10.6%, and the resin adsorption capacity per unit mass is approximately 111.5 Bq / g, both significantly lower than those of Example 1. These results demonstrate that relying solely on solid-liquid adsorption results in low mass transfer efficiency and limited hydrogen / tritium isotope exchange. The introduction of a carrier gas significantly enhances the gas-liquid-solid three-phase contact and interface renewal, thereby improving the tritium removal effect.

[0088] Comparative Example 2: The only difference between Comparative Example 2 and Example 1 is that no solid adsorbent material was added.

[0089] The test results of Comparative Example 2 show that, without solid adsorbent material, the single-stage tritium removal rate is only 4.8%, significantly lower than that of Example 1. These results indicate that relying solely on the carrier gas to carry and migrate tritized water vapor is insufficient to achieve ideal tritium removal efficiency. Solid adsorbent material plays a crucial role in this invention in promoting hydrogen / tritium isotope exchange and improving tritium removal efficiency.

[0090] Comparative Example 3: The only difference between Comparative Example 3 and Example 1 is that no cold trap unit was added.

[0091] In Comparative Example 3, the lack of a condensation and recovery stage resulted in the inability to effectively collect low-concentration tritium water vapor, leading to a significant decrease in tritium water collection efficiency. Although the cold trap unit has a limited direct impact on the single-stage tritium removal rate, it plays a crucial role in the effective recovery of tritium-containing vapor and the overall process integrity, and is an important component of this invention for achieving solid-liquid-gas synergistic tritium removal.

[0092] Comparative Example 4: The only difference between Comparative Example 4 and Example 1 is that the solid adsorbent material was replaced by a sulfonic acid-type strong acid cation exchange resin with a molecular sieve (purchased from Green New Source Environmental Protection, 5A type molecular sieve), while other experimental conditions remained unchanged.

[0093] Analysis of the test results showed that when molecular sieves were used as solid adsorbents, the single-stage tritium removal rate was only 8%, significantly lower than the treatment effect achieved in Example 1 when using sulfonic acid-type strong acid cation exchange resin. These results indicate that different solid materials exhibit significant differences in their tritium removal capabilities. While molecular sieves possess a certain pore structure and adsorption capacity, their surface lacks sufficient strong acid proton exchange sites and exchangeable hydrogen sites, making it difficult to effectively promote the enrichment of tritized water on the solid surface, hydrogen / tritium isotope exchange, and further fixation. Therefore, their treatment effect in the system of this invention is limited. In contrast, the surface of sulfonic acid-type strong acid cation exchange resin contains a large number of sulfonic acid functional groups, exhibiting strong proton exchange capacity, which is more conducive to the hydrogen / tritium isotope exchange process, thus improving the tritium removal effect.

[0094] This invention has been described through the specific embodiments described above. Those skilled in the art should understand that various modifications and equivalent substitutions can be made to this invention without departing from its scope. Parts not described in detail in this specification are well-known to those skilled in the art. Furthermore, various modifications can be made to this invention for specific situations or circumstances without departing from its scope. Therefore, this invention is not limited to the specific embodiments disclosed, but should include all embodiments falling within the scope of the claims.

Claims

1. A method for gas-carrier co-treatment of tritium wastewater, characterized in that, The method is a three-stage synergistic extraction method for removing tritium using gas phase, liquid phase, and solid phase, including at least one single-stage processing step, each of which specifically includes the following steps: Step 1): The tritium wastewater to be treated is introduced into a closed tritium removal reactor, solid adsorbent is added, and the reaction is carried out at a temperature of 25±2℃ for 12~72h to form a liquid-solid two-phase system. Step 2): The carrier gas source is introduced into the inner cavity of the tritium removal reactor through a gas distributor. The reaction occurs at a temperature of 5–100°C, forming a gas-liquid-solid three-phase contact structure. At the same time, a carrier gas flow carrying tritized water vapor is formed. The tritium activity concentration in the tritized water vapor is lower than the tritium activity concentration in the tritium wastewater. Step 3): The carrier gas flow is introduced into the cold trap unit and condensed and separated at -20 to 10°C to obtain treated water and carrier gas. The carrier gas is circulated back to the carrier gas source and the treated water is collected.

2. The method for gas-carrier co-treatment of tritium wastewater according to claim 1, characterized in that, The method includes a single-stage treatment process. Step 3) further includes: detecting the tritium activity concentration and tritium removal rate of the treated water; if the tritium activity concentration of the treated water is less than or equal to 100 Bq / L, it is stored or discharged; if the tritium activity concentration of the treated water is greater than 100 Bq / L, it is treated as a new batch of tritium wastewater and steps 1) to 3 are repeated.

3. The method for gas-carrier co-treatment of tritium wastewater according to claim 1, characterized in that, The method includes at least two single-stage processing procedures, which are connected in series or in parallel. When the single-stage treatment processes of the method are connected in series, step 3) of the last single-stage treatment process further includes: detecting the tritium activity concentration and tritium removal rate of the condensed and separated treated water; if the tritium activity concentration of the treated water in the last single-stage treatment process is greater than 100 Bq / L, it is recycled back to any single-stage treatment process as a new batch of tritium wastewater to be treated, and steps 1) to 3) are repeated; if the tritium activity concentration of the treated water in the last single-stage treatment process is less than or equal to 100 Bq / L, it is stored or discharged. When the single-stage treatment processes of the method are set in parallel, step 3) of each single-stage treatment process further includes: detecting the tritium activity concentration and tritium removal rate of the condensed and separated treated water; if the tritium activity concentration of the treated water in each single-stage treatment process is greater than 100 Bq / L, it is recycled back to each single-stage treatment process as a new batch of tritium wastewater to be treated, and steps 1) to 3) are repeated; if the tritium activity concentration of the treated water in each single-stage treatment process is less than or equal to 100 Bq / L, it is stored or discharged. When multiple single-stage treatment processes of the method are connected in series to form multiple sets of series single-stage treatment processes, and each set of series single-stage treatment processes is then connected in parallel; step 3) of the last single-stage treatment process of each set of series single-stage treatment processes further includes: the tritium activity concentration of the condensed and separated treated water needs to be detected. If the tritium activity concentration of the treated water of the last single-stage treatment process is greater than 100 Bq / L, then it is recycled back to any single-stage treatment process as a new batch of tritium wastewater to be treated, and steps 1) to 3) are repeated; if the tritium activity concentration of the treated water of the last single-stage treatment process is less than or equal to 100 Bq / L, then it is stored or discharged.

4. The method for gas-carrier co-treatment of tritium wastewater according to claim 2 or 3, characterized in that, The method treats n batches of tritium wastewater, where n≥2; the method further includes step 4): determining whether the solid adsorbent material in the tritium removal reactor needs to be replaced based on the tritium removal rate detected in step 3); when the tritium removal rate of the nth batch of treated water decreases by K compared to the tritium removal rate of the first batch of treated water, and K≥40%, the tritium-enriched solid adsorbent material is discharged from the tritium removal reactor, and new solid adsorbent material is added; the tritium-enriched solid adsorbent material is treated as tritium-containing solid waste.

5. The method for gas-carrier co-treatment of tritium wastewater according to claim 1, characterized in that, In step 2), the carrier gas is one or a combination of two of inert gases or weakly reactive gases, and the flow rate of the carrier gas is 0.001 to 10 L / min. In step 1), the mass ratio of the solid adsorbent material to the tritium wastewater is (1:1) to (1:10), and the volume ratio of the carrier gas introduced in step 2) to the tritium wastewater is (1:100) to (1:1).

6. A system for gas-carrier co-treatment of tritium wastewater, characterized in that, The system is used to implement the gas-carrier co-treatment method for tritium wastewater as described in any one of claims 1 to 5; The system includes one or more tritium removal units and a carrier gas source, the carrier gas source being used to store the carrier gas; the carrier gas is one or a combination of two of inert gases or weakly reactive gases, and each of the tritium removal units performs a single-stage processing procedure; The tritium removal unit includes a tritium removal reactor, a flow control unit, a cold trap unit, a gas loop pipeline, and a tritium water inlet pipeline. The flow control unit is a control valve. The tritium removal reactor is an openable sealed unit, including an inner cavity for containing tritium wastewater and solid adsorbent material, 1 to 5 gas distributors disposed on the inner wall of the tritium removal reactor, and a tritium removal reactor inlet and a tritium removal reactor gas outlet disposed on the inner wall of the tritium removal reactor; both the tritium removal reactor inlet and the tritium removal reactor gas outlet are equipped with flow control units. The gas distributor is connected to the carrier gas source via a pipeline, and the gas inlet of the gas distributor is equipped with a flow control unit; The gas outlet of the tritium removal reactor is connected to the cold trap unit. The gas inlet of the cold trap unit is equipped with a gas flow control unit. The gas outlet of the cold trap unit is connected to the carrier gas source through a gas loop pipeline. The tritium water inlet pipeline is connected to the water inlet of the tritium removal reactor. When the system has multiple tritium removal units, the tritium removal units are connected in parallel or in series. When the detritium removal units are connected in series, the outlet of the cold trap unit of the previous detritium removal unit is connected to the inlet of the detritium removal reactor of the next detritium removal unit.

7. The system for gas-carrier co-treatment of tritium wastewater according to claim 6, characterized in that, The inert gas is argon or helium, and the weakly reactive gas is nitrogen or air.

8. The system for gas-carrier co-treatment of tritium wastewater according to claim 6, characterized in that, The solid adsorbent material is a material containing hydrogen-containing functional groups and / or ion exchange groups that can participate in hydrogen / tritium isotope exchange, and the solid adsorbent material is a hydrophilic polymer adsorbent material.

9. The system for gas-carrier co-treatment of tritium wastewater according to claim 8, characterized in that, The solid adsorbent is a sulfonic acid type strong acid cation exchange resin, or a modified sulfonic acid type strong acid cation exchange resin, or polyvinyl alcohol. The resin backbone of the sulfonic acid type strong acid cation exchange resin is cross-linked polystyrene or acrylic acid copolymer, and the surface of the modified sulfonic acid type strong acid cation exchange resin contains -SO3H functional groups.

10. An application of a gas-carrier co-treatment system for tritium wastewater, characterized in that, The system is the gas-carrier co-processing system for tritium wastewater as described in any one of claims 6 to 9. The system is applied to the reduction of low-to-medium concentration tritium wastewater and the recovery of tritium resources generated by nuclear power plants, research reactors, isotope production devices or nuclear facilities. The tritium activity concentration of the low-to-medium concentration tritium wastewater is 1 MBq / L to 100 MBq / L.

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